Particles from vehicle tyre wear are the biggest source of nanoplastic pollution in the high Alps, a pioneering project has revealed.
Expert mountaineers teamed up with scientists to collect contamination-free samples and are now scaling peaks to produce the first global assessment of nanoplastics, which are easily carried around the world by winds.
Millions of tonnes of plastic waste are dumped in the environment and much is broken down into small fragments. Microplastics were already known to have polluted the entire planet, from the summit of Mount Everest to the deepest oceans.
However, nanoplastics are even tinier and have been difficult to collect and analyse. Researchers are concerned about the health impact of ubiquitous plastic pollution, and nanoplastics may be even more dangerous than microplastics as they are small enough to penetrate cell membranes and remain lodged in the body.
“We were really glad that these initial results [from the Alps] were good,” said Dr Dušan Materić, at the Helmholtz Centre for Environmental Research in Leipzig, Germany. “Then we thought about what to do next, and said: ‘Let’s go crazy, let’s do it globally.’”
“It will be the first study of global background nanoplastic pollution,” he said. “We need to establish that baseline so we can come back in future decades and see if things have got better or worse. It is a pioneering study, putting this issue on the map.” The mapping will also help identify the sources of the nanoplastics and guide efforts to reduce the pollution.
Since the Alpine expeditions, mountaineers have obtained high-altitude samples of glacier snow from the Mountains of the Moon on the Uganda-Congo border, as well as from Bolivia, Georgia, Kyrgyzstan, Nepal, New Zealand and the south pole and Ellsworth Mountains in Antarctica.
In 2025, the Global Atmospheric Plastics Survey plans to get further samples from Svalbard and Iceland in the Arctic, as well as Mount Everest, India, Wyoming and Alaska in the US, and northern Canada, plus further European samples from the Spanish Pyrenees, Poland and Norway.
“These remote places are very important to be analysed because you want to cover as much of the world as possible,” said Materić. “But it would be impossible without the mountaineers.”
Taking samples from very isolated places avoids local sources of nanoplastics dominating the readings, and using glacier snow means only particles falling from the sky are collected.
The Alpine survey, published in the journal Scientific Reports, found nanoplastics in five of the 14 sites sampled in the French, Swiss and Italian Alps. The most abundant nanoplastic was tyre particles (41%), then polystyrene (28%) and polyethylene (12%). Each tyre on the world’s 1.6bn vehicles can lose 4kg during its lifetimes and may be the largest source of tiny plastic pollution.
Given the pervasive pollution of the planet with plastic, it was crucial to avoid contamination. The team developed a collection method that avoided contamination from the gear and clothing of the mountaineers, much of which is made from plastic. A further complication was that the collection kit had to be light. “These are a pretty hardcore expeditions – if you give the mountaineers too much weight, they will struggle,” said Dr Al Gill, who led the Alpine expedition.
The results showed that collecting triplicate samples of snow in small glass vials, plus a blank sample as a control, delivered uncontaminated readings.
Prof Andreas Stohl, at the University of Vienna, who was not part of the study team, said a global map of nanoplastics would break important new ground. He said nanoplastics were of particular concern for health as, unlike most microplastics, they could penetrate the lungs and enter the bloodstream.
The Alpine samples were collected in summer, and Stohl said that could complicate the interpretation of the results. Summer melting could concentrate the nanoplastics or in other circumstances flush them away, he said, and snow that had lain for months could collect nanoplastics from different source regions as the winds changed.
Another group of explorers are also taking micro- and nanoplastic samples in remote places. Mission Spiritus has just completed a 1,000km traverse of Oman’s vast desert landscape. The team endured sandstorms and blistering temperatures and traversed some of the highest sand dunes in the world to collect 52 sand samples for analysis at Columbia University’s Lamont-Doherty Earth Observatory.
People are already known to consume tiny plastic particles via food and water, as well as breathing them in. Microplastics have been discovered in human blood, semen and breast milk and in brains, livers and bone marrow, indicating profuse contamination of people’s bodies. The impact on health is as yet unknown but microplastics have been shown to cause damage to human cells in the laboratory and have been linked to strokes and heart attacks.
